Air pollution caused by industry and other human-made sources is a determinant of health that continues to be largely overlooked despite its disastrous consequences. In 2012 the World Health Organization estimates that seven million people died as a result of pollutants in the air people breathe, this includes both indoor and outdoor air quality.

While many countries have banned smoking in public places it is less likely to see a similar ban on toxic emissions from cars or coal-fired power plants, although there have been attempts in limiting them. Many outdoor air pollution deaths are linked to heart disease and stroke. Health risks from air pollution is a major problem in urban areas throughout the world, but especially in cities in developing countries such as Kathmandu, Dhaka and Beijing.

Both Nepal and Bangladesh rank at the bottom of the air quality ranking from the Environmental Performance Index. China is just above Nepal and its air pollution problems have been well publicised as much could be done to mitigate the problems caused by poor air quality.

This satellite image taken January 2013 shows the extent of air pollution in China: